Gypsum wallboard is commonly used, in any of several different forms, in constructing interior walls and ceilings. In its most common form, a cream-colored face paper forms the wall exterior, the joints are covered by a setting or drying cementitious material, and the resultant monolithic wall is painted. The cream color of the face paper is provided by the choice of fibers used in the surface ply in its manufacture and/or dyes incorporated therein.
Other forms of gypsum board have been developed and marketed, with the aim of reducing the labor required in constructing, finishing and decorating the wall. These other forms generally involved substantial increases in the product cost, and met with little success unless they also incorporated a relatively maintenance-free surface, providing the justification for the substantial increase. In such cases, the increase in cost has generally been such that it was hard for consumers to justify except in large commercial structures, where subsequent maintenance costs are of substantial importance.
One problem that is faced in any attempt to provide a predecorated web of paper to be used in the subsequent manufacture of a paper-covered, gypsum-core wallboard is the necessity of providing a durable surface while maintaining sufficient porosity through the predecorated paper so that, after the gypsum and paper have been combined, the newly formed boards can be dried by high temperature removal of the access water in the core through the predecorated face paper. Prior attempts to provide predecorated face papers for use in making gypsum board generally involved a coating which decreased porosity excessively. One prior solution to this problem, described in Veschuroff U.S. Pat. No. 3,694,298, suggests embossing the paper after it is coated, possibly using several embossing steps, until the porosity desired is achieved.
A lower cost, predecorated, substantially maintenance-free gypsum wallboard, which can Justify its increased cost, relative to regular cream-faced gypsum wallboard, in home construction, particularly prefabs, is always being sought.